Means for stabilizing air



Jan. 12, 1943. J. M. CARROLL 2,308,439

MEANS FOR 'STABILIZING AIR Filed 001;. 31, 1940 I IN VEIY TOR y JAMES .CARROLL A TTORNE Y Patented Jan. 12, 1943 UNITED STATES PATENT- OFFICE MEANS'FOR. smnmzme Am James M. Carroll, Philadelphia, Pa., asaignor to Monarch Manufacturing Works, Inc., Philadelphia, Pa... a corporation of Delaware Application October 31, 1940, Serial No. 363,717

2 Claims. (Cl. 158-15) tively high CO2 without smoking, and this can only be effected if the air directed to the combustion chamber is properly controlled.

I have found that merely increasing or decreasing the volume of air or increasing or decreasing the pressure of air supplied to the furnace combustion chamber will not provide proper and emcient combustion, or produce a relatively high CO2. Due to the wide range of nozzle capacity, such as from .60 gallon capacity to 4.50 gallon capacity, it is highly desirable that apparatus for stabilizing and directing the air cover a plurality of nozzle sizes. I

It is a primary object of my invention to provide apparatus adapted to be used with a conventional oil burner for stabilizing, directing, and guiding air fed-to the furnace combustion chamber, whereby the combustion eificiency may be relatively increased.

Another object of my invention is to provide apparatus of the above type adapted to be used with nozzles of varying sizes or capacities.

A still further object of my invention is to provide apparatus of the above type which is economical of manufacture and installation.

According to the invention, air stabilizing and directing apparatus comprising a hub with angularly arranged blades thereon is disposed rearwardly of a cone ring secured to the discharge end of the blast tube, and the fuel supply pipe is projected through the hub. All of the blades are disposed at substantially the same angle to the hub axis and extend across the hub surface. Each blade extends substantially to the leading edge of an adjacent blade, whereby air is substantially prevented from moving axially along the hub, but is defiected'angularly of the hub. I have found that with the above described arrangement that at least CO2 can be produced with nozzles having a capacity of .60 gallon to 4.50 gallons and larger. The angularity of the blades relative to a plane at right angles to the hub axis is particularly important, and I have found that to give the desired results the angularity of the blades relative to such plane should be within a range of from 30 to A stabilizer with the blades arranged at a given angle can be used for several size nozzles, such as from .60 gallon capacity to 1.35 gallon capacity; then, by using the same stabilizer and merely changing the cone ring, the range can be increased to include nozzles up to 2.25 gallons capacity, depending upon the static pressure immediately in the rear of the stabilizer or between .the stabilizer and fan. For larger size nozzles,

the angularlty of the stabilizer blades may be changed and'a cone ring having a larger opening may be employed, or the static-pressure may be increased, whereby the range can be extended.

The drawing illustrates embodiments of the invention and the views therein are as follows:

Figure 1 is an elevational view, partially in section, of an oil burner embodying my invention,

Figure 2 is a fragmentary sectional view similar to Figure 1, but wherein a different type of cone ring is used,

Figure 3 is a front elevational view of the stabilizer shown in Figures 1 and 2, looking from the discharge end of the blast tube,

Figure 4 is a side view ofthe stabilizer of Figure 3,

Figure 5 is a rear elevational view of the stabilizer of Figure 4, looking towards the discharge end of the blast tube,

Figure 6 is a section along line 68 of Figure 3, and

Figure 7 is a fragmentary perspective view of the stabilizer.

Referring now to the drawing, I have indicated at Ill the air blast tube of an oil burner adapted to have air forced therethrough in the usual manner by a fan. Mounted on the end of the tube I0 is a cone ring ll having a tapered wall I 2 and a central restricted discharge opening l3. The fuel supply pipe, indicated at It, has the usual nozzle ii at the end thereof to which oil will be supplied under suitable pressure.

A stabilizer, generally indicated at H, comprises a hub l8, and a multiplicity of blades l9 disposed around the hub. The blades l9 extend angularly across the hub surface and a trailing edge of one blade is substantially longitudinally aligned with the leading edge of an adjacent blade. In other words, the edges of adjacent blades extend substantially to or closely parallel to a plane including line X-X parallel to the hub axis. [my desired number of blades may be used, although I have found that a stabilizer with eight blades operates very satisfactorily. The angularity of the blades relative to a plane including the line Y-Y extending at right angles to the hub axis may be altered from 30' to 45. and I have found that with a greater or lesser angularity than the limits mentioned satisfactory operation could not be obtained. However, the angularity of each blade on a given stabilizer relative to the plane including the line Y-Y should be substantially the same, but the angularity should .be increased for larger capacity nozzles. For example, I have found an angle of 40 to be satisfactory for nozzles from 2.50 to 4.50 gallons capacity depending upon the size of the air blast tube and static pressure.

It will be noted that the blades l9 extend from hub i8 substantially to the inner walls of tube i0, so that a snug fit is provided between the stabilizer and the tube. Although I have shown the blades as being integral with the hub it is understood that the blades may be integrally secured to the blast tube and may detachably support the hub at their radially inner edges. Further, the blades may be integrally secured to both the tube and hub, the primary purpose being to position blades intermediate the hub and the inner walls of the tube to prevent an excess longitudinal movement of air around the stabilizer towards the combustion chamber, and also to control the angularity of the blades within definite limits.

However, for certain operating conditions the blades I 9 may be spaced from the inner walls of tube i rather than extending substantially to the tube inner wall, as shown in Figures 1 and 2. By spacing the blades from the inner walls of tube Iii a portion of the air will be permitted to continue in a longitudinal direction rather than be deflected angularly through contact with blades l9. For example, it might be desirable to pass a portion of the air longitudinally to eliminate a pulsating condition in the system, or in the event that it is desired to employ a large capacity nozzle and suillcient air could not be otherwise transmitted to the combustion chamber because of the limited static pressure available.

I prefer that the trailing edge 2| of one blade be substantially longitudinally aligned with the leading edge 22 of an adjacent blade, or that these edges be in slight overlapping relation to deflect substantially all the air moving towards the combustion chamber through the tube i0 into a plurality of angular streams. However, I have found that the edges 2| and 22 may be slightly spaced to provide a gap therebetween, and that if this gap does not exceed one-quarter inch that the results obtained are not appreciablyy changed.

If the nozzle size or capacity is increased, the rate at which oil is delivered to the combustion chsamber in a given interval is increased and an additional volume of air is required. This increased volume of air can be obtained by increasing the angularity of the blades relative to the plane including the line Y-Y, whereby the direction of the divided air streams passing between the blades more closely approaches a longitudinal direction. Also, the volume of air can be increased by enlarging the discharge opening i3 of the cone ring. However, I have found that with a given static air pressure, equal hub diameter of the stabilizer, equal discharge opening through the end of the tube, and with the blades set at a given angle, that there is substantially no increase in air volume by increasing the diother words, only a given volume of air will passed around the stabilizer and increasing the size of the air blast tube, while maintaining the same static'pressure, will not appreciably change the volume of air passing to the combustion chamber. However, it is understood that for a given-size air blast tube and a given size stabilizer, that a larger size nozzle may be successfully employed by increasing the static pressure.

The stabilizer ll should be positioned rearwardly of the cone ring, and I have found that if the distance from the front face of the cone mg to the front face of the stabilizer is maintained at approximately flve inches that best results are obtained for all sizes of nozzles. However, for certain size nozzles, and depending upon the static pressure, this distance may be changed without appreciably changing the result obtained or without reducing the CO2.

The particular manner of igniting the fuel and air' mixture constitutes no essential part of my invention, and in the present instance, I have shown electrical ignition means and the hub is perforated to receive insulators 23 carrying wires 24 and 28 which terminate slightly forwardly of the nozzle to provide a spark gap therebetween whereby the fuel and air mixture may be ignited in the usual manner by supplying electrical current to wires 24 and 26.

I preferably taper the rear face of hub It as indicated at 21 to provide a smooth flow of air to the passages intermediate the blades i9, but I have found that such taper is not necessary, and that the hub may be made cylindrical over its entire surface, may be tapered over its entire surface to progressively increase the hub diameter from the rear to the front face thereof, or

that a reverse taper may be provided, whereby the hub diameter is progressively decreased as the front face of the hub is approached. Also, the size or diameter of the hub has no appreciable effect on the operating results, but the hub should be suillciently large to support the insulators 23 in spaced relation to the fuel pipe it if electrical ignition means are employed.

As best illustrated in Figure 4, the trailing edges 2i of the blades are inclined at a slight angle radially outwardly, such as 5, and the leading edges 22 are also inclined angularly outwardly, the inclination of these edges resulting from the longitudinal alignment of adjacent edges'2l and 22. Also, the edges 2| are preferably cut transversely of the hub and the edges 22 are cut generally longitudinally to offer a minimum impedance to the smooth flow of air between adjacent blades.

The operation of the apparatus will now be described. Oil is fed through the supply pipe it under substantially constant predetermined pressure from a pressure regulating valve, and thence to the nozzle i8. The oil is issued from the orifice of the nozzle or nozzles into the combustion chamber at a substantially constant angle or in the form of a maintained conical spray. Air under static pressure will flow in a longitudinal stream through the blast tube It, and upon reaching the stabilizer will be directed into a plurality of substantially equally spaced 'angular streams extending in the same general ameter of the air blast tube and stabilizer. In 76 mate combustible mixture when ignited produces a relatively high percentage of CO: without appreciable smoke and results in a substantially transparent flame immediately beyond the nozzle, shading to a bluish and then yellowish flame. With the smallest practical size nozzle, such as .60 gallon capacity, the flame retention is perfect, under operating conditions.

Referring now to Figure 2, I have shown a somewhat different form of cone ring 3|. Cone ring 3| is generally similar to cone ring H, but a multiplicity of diagonal blades 32 are formed on the inner wall of the cone ring. The angularity of each blade 32 relative to a transverse plane is substantially the same and the radial inner edges of blades 32 are generally horizontal and substantially equidistant from the cone ring axis. I have found that either type of cone ring may be usedwith the stabilizer described. The blades 32 of cone ring 3| may extend in the same general direction as the blades I! of the stabflizer, or in reverse direction. Further, I have foimd that when abnormal throbbing or pulsating conditions are encounteredin the boiler of an oil burner system it is possible to eliminate these pulsations by arranging the blades of the cone ring in a reverse direction to those on the stabilizer whereby the divided streams of air passing angularly through the stabilizer will be disrupted prior to being discharged through the cone ring to the combustion chamber.

The above described device was evolved after considerable experimental work, and has been thoroughly tested. It will permit burners of varying capacities to produce a minimum of 10% C: without appreciable smoke, and in some instances l4';% C0: has been produced.

Although I have illustrated the fuel pipe M as being projected through the hub l8 of the stabilizer, it is understood that this arrangement is not essential and the fuel pipe may be disposed externally of air blast tube It and projected through the air blast tube at a desired point such as forwardly of the stabilizer or between the stabilizer and the cone ring.

Although I have shown and described preferred forms of my invention, it is contemplated-that numerous and extensive departures may be made therefrom without departing from the spirit of my invention and the scope of the appended claims.

The invention is hereby claimed as follows:

1. In an oil burner, the combination with an air blast tube having a restricted discharge opening, of means for stabilizing and directing air passing through the tube, said means comprising a hub within the tube having a cylindrical portion and a reduced frusto-conical portion, the frusto-conical portion being more remote from the discharge opening of the tube and adapted to direct air over the cylindrical portion, a plurality of straight blades extending outwardly from the hub cylindrical portion, each of said blades extending diagonally in the same general direction and having substantially the same angle with a plane extending at right angles to the hub axis, the trailing and leading edges of each blade diverging outwardly from the hub whereby the edges of adjacent blades will be in substantially longitudinally alignment, the trailing edge of each blade terminating radially inwardly at the cylindrical portion and radially outwardly substantially in the plane of the hub rear face,

and the hub being perforated for projecting an oil supply pipe therethrough.

,2. In an oil burner, the-combination with an air blast tube having-a restricted discharge opening adapted to have air under pressure forced therethrough and a fuel supply pipe therein terminating in a spray nozzle adjacent said discharge opening, of air stabilizing and directing means disposed within said tubular member, said means comprising a hub having a cylindrical portion and a reduced frusto-conical portion relatively remote from the discharge opening, a plurality of flat blades substantially equally spaced around said hub, and fixed to the cylindrical portion thereof, the blades extending outwardly from the hub surface to the inner walls of the tubular member, each of said blades extending diagonally relative to the hub, and at substantially the same angle to a plane extending at right angles to the hub axis, the maximum angularity of said blades relative to said plane being the trailing edge of each blade terminating radially inwardly at the hub cylindrical portion and radially outwardly substantially in the plane of the hub rear face, and the blades being spaced so that the edges of adjacent blades are substantially longitudinally aligned.

JAMES M. CARROLL.

- CERTIFICATE (F CORRECTION. Patent Ho.i2,308,1+59. A January 12, 1915.

- J'AMESH. CARROLL.

It is hereby certified that error appe are in the printed specificatiop of the above numbered patent requiring correctiox; ae followg: Page 2,.11rat column, line 20, before "mast" insert "air"; page 3, second column,

li e 19, claim 1, for "longitudinally" read --'-.;I.ong1tudina1- and that the said Letters Patent should be read v1thth is correction therein that the same may conform to the record of the case in the Patent Office.

Signed and. sealed e115 llpthday of March, A. 1 19%.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

